The present invention relates to the supply of fuel and air mixture to a gaseous fuel burner and particularly relates to supplying a fuel/air mixture to gaseous fuel burners employed for cooking. In particular, the invention relates to supplying a fuel/air mixture to gaseous fuel burners for rangetops and cooktops utilized in household cooking appliances which are manufactured in high volume mass production.
Heretofore, the tubular supply arrangements for the fuel/air mixture, or mixer tubes widely used in the manufacture of household rangetop and cooktop burners have been formed with an individual air-aspirating venturi tube connected for supplying the top burners individually from a gas supply manifold. It is known to form the fuel/air venturi supply or mixer tubes by stamped shells or half tubes joined together at their margins to form a completed tube assembly. In a co-pending application, Ser. No. 609,203 filed Mar. 1, 1996 entitled "Mixer Tube Assembly For Fuel Gas Burner" and assigned to the assignee of the present invention, it was disclosed to form the fuel/air supply or mixer tube for plural top burners from stamped half shells formed from individual sheets of material joined together to form individual spaced venturi mixer tubes or passages for connection at the inlet end of the tubes to a manifold and at the outlet end to individual burners. However, in fabricating such plural burner mixer tubes from sheet material and joining the sheets, it has been found that there is leakage of the fuel/air mixture between the sheets from one tube to the other. If this leakage is not controlled, the fuel/air mixture can flow between the passages and to a burner which has not been ignited, thereby creating a hazardous condition.
Accordingly, it has been desired to provide a relatively low cost way or means of forming a fuel/air supply or mixer tube assembly from individually formed shells made from sheet stock and joined in such a manner as to prevent leakage between the individual burner tube passages and in such a was as to minimize the manufacturing costs.